It turned out to be by eminent pre-Raphaelite artist William James Webbe and has been valued at about £70,000 by experts at the auction house.

‘It’s a complete shock – I’ve never won anything beyond the odd thing from a tombola,’ said Ms Cordery.

It has since been discovered that the painting, which measures 18in by 10in, was exhibited at the Royal Society in 1856, and praised by the leading art critic of the time, John Ruskin, who wrote that it was ‘a careful study, the brown wing excellent’.

Ms Cordery, 66, was sure she had never seen the painting before she set to work in the attic of her Edwardian semi in Basingstoke, Hampshire.

But her partner James Ravenscroft, 69, recalled being given it by his mother ten years ago among other ‘bits and bobs’.